Many players, myself included, keep on getting kicked for a wrong signature on a random stock Arma 3 file. This just happened despite doing a verify of the files right before joining the server, so I am fairly confident that it is not an actual issue with one of the files, but a false positive that is being generated.

I have also noticed that it often happens fairly soon after first starting Arma 3 and joining the server, but once the server has been rejoined after the kick (without shutting Arma 3 down) it is often possible to play for much longer without it happening again.